Prefabricated steel joist adapted for the reinforcement of floors



June 21, 1966 E. TERSIGNI 3,256,670

PREFABRICATED STEEL JOIST ADAPTED FOR THE REINFORCEMENT OF FLOORS 6 Sheets-Sheet 1 Filed July 15, 1962 INVENTOR MJJMM ATTORNEYS June 21, 1966 E. TERSIGNI 3,256,670

PREFABRICATED STEEL JOIST ADAPTED FOR THE REINFORCEMENT OF FLOORS Filed July 13, 1962 6 Sheets-Sheet 2 Y\ a 15 l INVENTOR BY wmwdw ATTORNEYS June 21, 1966 E. TERSIGNI 3,256,670

PREFABRICATED STEEL JOIST ADAPTED FOR THE REINFORCEMENT OF FLOORS Filed July 15, 1962 6 Sheets-Sheet 3 9W4 INVENTOR ATTORNEYS June 21, 1966 E. TERSIGNI 3,255,670

PREFABRIGATED STEEL JOIST ADAPTED FOR THE REINFORCEMENT 0F FLOORS Filed July 13, 1962 6 Sheets-Sheet 4 52 E e E 3 E"- "E a a E is E E N\ i E "-5 k INVENTOR ATTORNEY June 21, 1966 E. TERSIGNI 3,256,670

PREFABRICATED STEEL JOIST ADAPTED FOR THE REINFORCEMENT OF FLOORS Filed July 15, 1962 6 Sheets-Sheet 5 INVENTOR BY UJMWK-M,

ATTORNEYS June 21, 1966 TERs|GN| 3,256,670

PREFABRICATED STEEL JOIST ADAPTED FOR THE REINFORCEMENT OF FLOORS Filed July 13, 1962 6 Sheets-Sheet 6 Fly. [8 ii? INVENTOR BY MJLM MPM ATTORNEYS United States Patent 3,256,670 PREFABRICATED STEEL JOIST ADAPTED FOR THE REINFORCEMENT 0F FLOORS Ennio Tersigni, Via Salaria 330B, Rome, Italy Filed July 13, 1962, Ser. No. 209,510 Claims priority, application Italy, July 26, 1961, 13,507/ 61 1 Claim. (Cl. 52-634) The object of this invention is to provide girders made of steel sheets, for the reinforcement of building floors, suitable to be manufactured at low cost, in mass production to obtain uniformly sized elements adapted to be easily and quickly installed.

This invention provides a double tubular construction with a connection web, obtained from a steel sheet having a thickness from 1 mm. to 3 mm., by an automatically performed shaping process and having any desired length. The raw steel sheet can be previously punched in order to obtain a particular array of holes causing the metal joist to form, in reinforced concrete, an integral unit with the concrete mix which enters through said holes of both the punched tubular members forming the upper and lower wings, and of the web of the joists, so that these will :be entirely embedded within the concrete, particularly when vibration is used.

The particular profile of the joist allows it to be rigid even during the concrete casting and setting stages and to form a support for the casing made of a ribbed sheet for retaining the casting. The joists also form the skeleton and reinforcement of the floor structure.

Joists made of steel sheets for floor reinforcement can be utilized for the carrying structure of a building of reinforced concrete, or for buildings having bearing walls made of bricks or stones, by anchoring said joists to the reinforcing rods of the concrete in the first case or by arranging them within the connection seams in the second case.

The joists can also form the carrier units of the floor and relieve the stresses acting on cement pillars or on iron columns or on bearing walls.

This invention will be hereinafter described only by way of non-limitative example with reference to the attached drawings showing one preferred embodiment of the said invention.

In the drawings:

FIG. 1 is a cross-sectional view of the joist according to this invention;

FIG. 2 is a partial side elevation;

FIG. 3 is a bottom plan view;

FIG. 4 is a top plan view;

FIG. 5 is a perspective view;

FIG. 6 is a cross-sectional view of two coupled carrying joists, with a relief joist and associated connecting plates:

FIG. 7 is a top plan view corresponding to FIG. 6;

FIG. 8 shows the detail of the upper connecting plate, in top plan view;

FIG. 9 shows a cross-sectional View taken along the plane IXIX of FIG. 8;

FIG. 10 shows a cross-sectional view taken along the plane X-X of FIG. 8;

FIG. 11 shows the lower connecting plate, in bottom plan view;

FIG. 12 shows a cross-sectional View of FIG. 11 taken along the plane XIIXII of said figure;

FIG. 13 shows a cross-sectional view taken along the plane XIII-XIII of FIG. 11;

FIG. 14 shows a longitudinal section-a1 view of the plate of FIG. 11;

FIG. 15 shows the profile of a relief joist with a lower channel for a simple rest;

3,256,670 Patented June 21, 1966 FIG. 16 is a side elevational view;

FIG. 17 is a perspective view of the joist of FIG. 15;

FIG. 18 is a front elevational view of the relief joist with a reversed V plate;

FIG. 19 is a side view corresponding to that of FIG. 18;

FIG. 20 is a top plan view.

With reference to FIGS. 1 to 5, this invention provides a metal joist manufactured from steel sheet, sheared and bent by an industrial, continuous and automatic machining. The joist comprises a base or supporting portion 1 which is connected to the web 2 by means of the two inclined sides 3, and ends at its top with a tubular rib i, the top of which is provided with a continuous ridge 5.

As shown in the FIGURES 3 and 4, holes 6 can be provided in the base plate, while other holes 7 start from the sides 3, and pass through the web 2 and the tubular upperrib 4, so as to obtain a light-weight shape without affecting its strength. As aforesaid, the joist is manufactured from a single steel sheet which is bent and welded along the junction edge 8.

FIGURES 6 and 7 show two coupled joists 22 in twin arrangement, connected to a third joist 21 arranged transversely to the joists 22 to relieve the stresses acting thereon.

The connection of the joist 22 with the transverse joist 21 is obtained by an upper plate 9 and a lower plate It) which are shaped to engage both the joists 22 and transverse joist 21 so as to form a rigid unit thus avoiding punching, bolting or other connection devices requiring difficult operations.

The upper plate 9 (shown also in FIGURES 8 to 10) is provided with a longitudinal rib 11 resting on the ridge 5 of the relief joist and with two parallel ribs 12 which rest on the ridges of the two carrying joists located sideby-side. The connection of the upper joist portion is completed by folding the flange 13 against the associated side of the rib 4 of the outer joist.

Thelower connecting plate 10 (shown also in FIGURES 11 to 14) consists of two stiffening ribs 14 provided under the flange of the relief joist, two flanges 15 which are bent against the sides of said joist, and two cross-flanges 16 which are folded onto the outer sides of the two carrier joists located side-by-si-de, as shown in FIGURE 6. In FIGURES l5, l6 and 17 the joist rests on a metal support channel 17 to be used in case of simple support.

If the joist is to be connected to a support metal structure, as for instance a pillar or a girder of metal shape, a connecting plate It is provided having an inverted V shape and located transversely with respect to the head of the joist, said plate 18 being provided with fastening flanges 19 having holes 20 for the direct fixing by means of bolts or any other equivalent means.

This invention has been disclosed in one preferred embodiment and it will be apparent that various changes might be made in the form, construction and arrangement of the parts without departing from the scope of the invention.

What is claimed is:

A joist structure for reinforcement of building floors in concrete mixes comprising in combination a pair of joists arranged side by side and having a hollow lower support portion having in cross section an isosceles triangle shape, the apex of said triangle being directed upwardly, a hollow upper portion having in cross section an isosceles triangle shape, the apex of said triangle being directed downwardly and the leg of said last named portion opposite said apex having a dihedral shape with its apex extending upwardly, a pair of contiguous webs connecting said port-ions to one another, one of said webs forming a unit with said portions and the other web comprising projections of both portions welded to one another, said webs and portions having holes for embedding the joist within the concrete, a third similar joist arranged perpendicularly to said pair of joists, an upper plate having a central longitudinal groove engaging the upper portion of said third joist and two cross grooves engaging the upper portions of said joist pair, a lower plate having two upwardly turned pliable flanges for engaging the lower portions of said joist pair and two upwardly turned rigid flanges engaging the lower portion of said third joist, said upper and lower plate rigidly connecting said joist to :form a unit.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS 5/1960 France.

OTHER REFERENCES 10 The Lewen System: page 14, copyright 1912.

FRANK L. ABBOTT, Primary Examiner.

HENRY C. SUTHERLAND, Examiner.

15 M. O. WARNECKE, Assistant Examiner. 

